Category: MVC3

Introduction

Our roadmap towards Learning MVC

Pre-requisites

1. We have running sample application that we created in fifth part of the article series.
2. We have Entity Framework 4.1 package or DLL on our local file system.
3. We understand how MVC application is created (follow second part of the series).

Why Generic Repository

Unit of Work Pattern

• To manage transactions.
• To order the database inserts, deletes, and updates.
• To prevent duplicate updates. Inside a single usage of a Unit of Work object, different parts of the code may mark the same Invoice object as changed, but the Unit of Work class will only issue a single UPDATE command to the database.

Why use Unit of Work?

Using the Unit of Work

Creating a Generic Repository

using System;
using System.Collections.Generic;
using System.Data;
using System.Data.Entity;
using System.Linq;
using System.Linq.Expressions;

namespace LearningMVC.GenericRepository
{
public class GenericRepository where TEntity : class
{
internal MVCEntities context;
internal DbSet dbSet;

public GenericRepository(MVCEntities context)
{
this.context = context;
this.dbSet = context.Set();
}

public virtual IEnumerable Get()
{
IQueryable query = dbSet;
return query.ToList();
}

public virtual TEntity GetByID(object id)
{
return dbSet.Find(id);
}

public virtual void Insert(TEntity entity)
{
dbSet.Add(entity);
}

public virtual void Delete(object id)
{
TEntity entityToDelete = dbSet.Find(id);
Delete(entityToDelete);
}

public virtual void Delete(TEntity entityToDelete)
{
if (context.Entry(entityToDelete).State == EntityState.Detached)
{
dbSet.Attach(entityToDelete);
}
dbSet.Remove(entityToDelete);
}

public virtual void Update(TEntity entityToUpdate)
{
dbSet.Attach(entityToUpdate);
context.Entry(entityToUpdate).State = EntityState.Modified;
}
}
}

using System;
using LearningMVC.GenericRepository;

namespace LearningMVC.UnitOfWork
{
public class UnitOfWork : IDisposable
{
private MVCEntities context = new MVCEntities();
private GenericRepository userRepository;

public GenericRepository UserRepository
{
get
{
if (this.userRepository == null)
this.userRepository = new GenericRepository(context);
return userRepository;
}
}

public void Save()
{
context.SaveChanges();
}

private bool disposed = false;

protected virtual void Dispose(bool disposing)
{
if (!this.disposed)
{
if (disposing)
{
context.Dispose();
}
}
this.disposed = true;
}

public void Dispose()
{
Dispose(true);
GC.SuppressFinalize(this);
}
}
}

public GenericRepository UserRepository
{
    get
    {
        if (this.userRepository == null)
            this.userRepository = new GenericRepository(context);
        return userRepository;
    }
}

private UnitOfWork.UnitOfWork unitOfWork = new UnitOfWork.UnitOfWork();

public ActionResult Index()
{
    var userList = from user in unitOfWork.UserRepository.Get() select user;
    var users = new List();
    if (userList.Any())
    {
        foreach (var user in userList)
        {
            users.Add(new LearningMVC.Models.UserList() { UserId = user.UserId, 
              Address = user.Address, Company = user.Company, 
              FirstName = user.FirstName, LastName = user.LastName, 
              Designation = user.Designation, EMail = user.EMail, PhoneNo = user.PhoneNo });
        }
    }
    ViewBag.FirstName = "My First Name";
    ViewData["FirstName"] = "My First Name";
    if(TempData.Any())
    {
        var tempData = TempData["TempData Name"];
    }
    return View(users);
}

• unitOfWork.UserRepository ­­> Accessing UserRepository.
• unitOfWork.UserRepository.Get() -> Accessing Generic Get() method to get all users.

public MyController()
{
    this.userRepository = new UserRepository(new MVCEntities());
}

Details

public ActionResult Details(int id)
{
    var userDetails = unitOfWork.UserRepository.GetByID(id);
    var user = new LearningMVC.Models.UserList();
    if (userDetails != null)
    {
        user.UserId = userDetails.UserId;
        user.FirstName = userDetails.FirstName;
        user.LastName = userDetails.LastName;
        user.Address = userDetails.Address;
        user.PhoneNo = userDetails.PhoneNo;
        user.EMail = userDetails.EMail;
            user.Company = userDetails.Company;
        user.Designation = userDetails.Designation;
    }
    return View(user);
}

[HttpPost]
public ActionResult Create(LearningMVC.Models.UserList userDetails)
{
    try
    {
        var user = new User();
        if (userDetails != null)
        {
            user.UserId = userDetails.UserId;
            user.FirstName = userDetails.FirstName;
            user.LastName = userDetails.LastName;
            user.Address = userDetails.Address;
            user.PhoneNo = userDetails.PhoneNo;
            user.EMail = userDetails.EMail;
            user.Company = userDetails.Company;
            user.Designation = userDetails.Designation;
        }
        unitOfWork.UserRepository.Insert(user);
        unitOfWork.Save();
        return RedirectToAction("Index");
          }
    catch
    {
        return View();
    }
}

public ActionResult Edit(int id)
{
    var userDetails = unitOfWork.UserRepository.GetByID(id);
    var user = new LearningMVC.Models.UserList();
    if (userDetails != null)
    {
        user.UserId = userDetails.UserId;
        user.FirstName = userDetails.FirstName;
        user.LastName = userDetails.LastName;
        user.Address = userDetails.Address;
        user.PhoneNo = userDetails.PhoneNo;
        user.EMail = userDetails.EMail;
        user.Company = userDetails.Company;
        user.Designation = userDetails.Designation;
      }
    return View(user);
}

[HttpPost]
public ActionResult Edit(int id, User userDetails)
{
TempData[“TempData Name”] = “Akhil”;

try
{
var user = unitOfWork.UserRepository.GetByID(id);
user.FirstName = userDetails.FirstName;
user.LastName = userDetails.LastName;
user.Address = userDetails.Address;
user.PhoneNo = userDetails.PhoneNo;
user.EMail = userDetails.EMail;
user.Company = userDetails.Company;
user.Designation = userDetails.Designation;
unitOfWork.UserRepository.Update(user);
unitOfWork.Save();
return RedirectToAction(“Index”);
}

public ActionResult Delete(int id)
{
    var user = new LearningMVC.Models.UserList();
    var userDetails = unitOfWork.UserRepository.GetByID(id);

if (userDetails != null)
{
user.FirstName = userDetails.FirstName;
user.LastName = userDetails.LastName;
user.Address = userDetails.Address;
user.PhoneNo = userDetails.PhoneNo;
user.EMail = userDetails.EMail;
user.Company = userDetails.Company;
user.Designation = userDetails.Designation;
}
return View(user);
}

[HttpPost]
public ActionResult Delete(int id, LearningMVC.Models.UserList userDetails)
{
try
{
var user = unitOfWork.UserRepository.GetByID(id);

if (user != null)
{
unitOfWork.UserRepository.Delete(id);
unitOfWork.Save();
}

return RedirectToAction(“Index”);
}
catch
{
return View();
}
}

Conclusion

Introduction

Our Roadmap

Pre-requisites

1. We have the running sample application that we created in the third part of the article series.
2. We have EntityFramework 4.1 package or DLL on our local file system.
3. We understand how MVC application is created.

Code-First Approach

Procedure

public DbSet Users { get; set; }

using System;
using System.Collections.Generic;
using System.Data.Entity;
using System.Linq;
using System.Web;
using LearningMVC.Models;

namespace LearningMVC
{
public class MVCDBContext : DbContext
{
public DbSet Users { get; set; }
}
}

Our Heroes

var dbContext = new MVCEntities() ;
to
var dbContext = new MVCDBContext();

Job done. 

Conclusion